Its about a wife seeking revenge on her husband by hiring a prostitute to woo & win emotionally, only to bring his life down on the verge of a professional breakthrough and marriage to the prostitute? Prostitue sleeps with ex-husband and best mate.

One of these two:

Sweet Revenge 2001, http://www.imdb.com/title/tt0298566/
Or
Sweet Revenge 1990, http://www.imdb.com/title/tt0100725/